A wide variety of reporting systems have been developed for providing communication between a premise and a central monitoring facility. In the past, these reporting systems have been typically limited to commercial and residential security alarm systems, medical emergency systems, and environmental equipment monitoring systems. However, with the increasing development of wireless communications technology, the use and applications of reporting systems is expected to grow to encompass fleet management, remote utility metering, vending machine status, and many other commercial markets.
The key to the effectiveness and integrity of the reporting system provided often depends upon the means which are used to establish communications between the reporting unit provided at the premises and the monitoring equipment provided at the central monitoring facility. It has become well known in the industry that repetitive monitoring of the link between the premise and central monitoring facility provides an enhancement in reliability. These systems which implement a periodic monitoring of the communication link are commonly known as "supervised" reporting devices.
Aside from increased reliability in the communication link, there are several notable reasons why the use of a "supervised" system is desirable over the less sophisticated "unsupervised" systems. With respect to the use of the reporting system as a security alarm device, insurance companies often determine insurance rates based on the quality of electronic and/or automatic monitoring of the communication link between their commercial establishment or residence and a central monitoring facility. In fact, Underwriters Laboratories has established several grade levels which attach to the type and extent of monitoring provided. The highest grade or grade AA is attached to a supervised link which is monitored by a central monitoring station no later than 6 minutes after compromise in the link.
One supervised system for providing communications between the premises and the central monitoring facility is by means of direct wired telephone lines which connect the premise to the central monitoring facility. The drawbacks of such a system is the high installation expense and high usage fees as well as low availability. Another supervised system uses a switched telephone network commonly known as a derived channel system. Although the use of a derived channel system can be shared by more users, it forces telephone companies to add expensive equipment which does not provide an attractive return. The result is that these systems are not widely available and are limited to commercial areas where higher profitability on alarm systems can be expected.
Another supervised system involves the replacement of wired lines with wireless communications such as two-way radios. Radio systems are reliable because there is less of a likelihood of outside interference such as line tampering. Although in some respects more reliable than a wired system, two-way radio systems are subject to significant limitations in view of the regulatory constraints which are in place regarding the use of radio waves, and in terms of the number of frequencies which are available for use in a particular system, limiting the number of subscribers. In addition, the significant cost of installation and maintenance with the frequent use of such a system is often prohibitive for supervisory purposes. Consequently, their application is almost exclusively limited to non-supervised systems.
In U.S. Pat. No. 4,868,859 (hereinafter '859), issuing to Sheffer, lines 47-50, it was suggested that two-way radio communications be accomplished by means of the cellular telephone network. At first glance, this appears attractive because it incorporates an existing cellular communication infrastructure. The disclosure in Sheffer '859 suggests combining a supervised derived channel system with a non-supervised cellular telephone system to provide a more reliable redundant system. Specifically, Sheffer '859 teaches the use of a non-supervised cellular telephone due to the prohibitive expense as a; supervised system resulting from charges associated with the cellular telephone network. For example, each time the central monitoring facility monitors the link, a supervised call must be made over the cellular telephone network resulting in significant telephone charges. As is clearly evident from the above example, the cost of such a supervised wireless system is prohibitive to the average consumer.
It is therefore the primary object of the present invention to provide a highly reliable reporting system which is not cost prohibitive to the average consumer as are the previously available systems.
It is also an object of the present invention to provide a reporting system which utilizes a communications infrastructure which is universally accessible and widely available.
It is also an object of the present invention to provide a supervised wireless reporting system which is capable of providing a high degree of reliability without suffering from the significant drawbacks of the previously available wireless systems.
It also an object of the present invention to enable a central monitoring facility to provide a communicated message verification utilizing the same premise equipment yet through a separate wireless communications network.
It is also an object of the present invention to provide a reporting system which provides redundant equipment utilization in the event of localized equipment failure.
It is also an object of the present invention to provide a reporting system which is not limited in terms of the number of subscribers which may be connected to the system, as a result of technical or regulatory constraints.
It is also an object of the present invention to provide a reporting system which is capable of being adapted to and/or added to existing reporting systems, to the extent possible.
It is also an object of the present invention to provide a reporting system having the foregoing capabilities, yet which is inexpensive and easy to install, maintain and service.
These and other objects are achieved in accordance with the present invention by providing a supervised communications network which utilizes existing cellular telecommunications network frequencies to report information from a premise to a central monitoring facility. The present invention provides an input device for providing one or more messages by means of a digital signal to a transceiver module. The messages received by the transceiver module may be either a supervision message or event message. In one embodiment, the input device is an alarm system which provides a digital signal corresponding to a status of the alarm system.
The transceiver module associated with the premise may be a modified cellular telephone which is operable in one of the three following modes; supervision, event and wait. The transceiver module transmits the supervision or event messages on a preselected reverse control channel. The method of preselection is intended to select a reverse control channel which is inactive or not used by any proximately located cell site. The reverse control channel selected has a corresponding forward control channel which preferably has a signal strength below the range of -115 to -125 dBm and preferably is adjacent in frequency to a forward control channel having a signal strength below a range of -75 to -85 dBm. The selection of an inactive reverse control channel precipitates the above mentioned low signal strength forward control channel.
A message processor, placed at a site proximate to a predetermined cellular site, receives and decodes the messages transmitted from the transceiver module and transmits the messages to a central monitoring facility. The message processor may include one or more reverse control channel scanners for detecting an active reverse control channel. One or more reverse control channel receivers, operable with the reverse control channel scanners, receive and decode the messages detected by the reverse control channel scanners. A master module, operable with the reverse control channel scanners and the reverse control channel receivers, arranges and transmits the messages received by the message processor to the central facility by means of a standard modem.
It is anticipated that the present invention may be utilized in a network environment which may include multiple transceiver modules respectively located at multiple premises, and a message processor which receives and decodes multiple messages from respective multiple transceiver modules and transmits multiple messages to a central monitoring facility. In a similar manner, it is anticipated that there will be multiple message processors within the network 10.
A connection is provided between the transceiver module and a transducer such as microphone-speaker headset. While in supervision mode, the transceiver module repeatedly transmits supervision messages within a first preselected time interval. The preselected time interval is preferably between one and six minutes. While in an event mode, the transceiver module continuously transmits an event message for a second preselected time interval. Once the preselected time interval of the event message expires, the transceiver module enters the wait mode. While in wait mode, the transceiver module is connected to the headset and operates as a standard cellular telephone.
The present invention also pertains to a method of communicating information from a premise to a central facility using cellular telecommunications frequencies. The initial step in the method includes interfacing a transceiver module, associated with a premise, to an input device. The step is followed by the step of scanning multiple forward control channels using the transceiver module and determining a set of preselected criteria or characteristics such as the forward control channel number and a number indicative of a signal strength of the forward control number. The method continues with the step of storing the set of preselected criteria of one or more control channels in a data array and updating the predetermined criteria every predetermined interval. A predetermined interval may be the time it takes to scan of twenty one (21) forward control channels. The next step includes the step of selecting a forward control channel based on a comparison of the stored preselected criteria or characteristics and determining a reverse control channel corresponding to the selected forward control channel for transmission of the supervision or event message to the central facility. This step is followed by transmitting the message to a message processor either periodically every predetermined duration if the message is a supervision message, or continuously for a predetermined duration if the message is an event message. The method includes the step of transmitting the message received by the message processor to a central facility by forming a data package consistent with a standard reverse control channel message.
The step of selecting the forward control channel includes the steps of initially selecting multiple forward control channels having a signal strength remaining below a preselected threshold, eliminating those forward control channels initially selected if they are adjacent in frequency to a forward control channel which has a signal strength of a preselected value or higher, and randomly selecting one of remaining multiple forward control channels.
Further detail regarding the construction of a reporting system in accordance with the present invention may be had with reference to the detailed description which is provided below, taken in conjunction with the following illustrations.